Fig. 1.

(A) Sequence alignment of the S2 segment of Shaker (GI: 13432103), Kv1.2 (GI: 4826782), Nav1.1 domain I, II, III, and IV (GI: 115583677), Ci-VSP (GI: 76253898), KvAP (GI: 38605092), and Hv1 (GI: 91992155). The residue at position 290 (in Shaker) is colored (green for Phe, red for other amino acid). (B–D) Gating currents of the representative mutants F²⁹⁰W (B), F²⁹⁰N (C), and F²⁹⁰A (D) during the indicated activation (red traces) or deactivation (blue traces) protocol. Capacitive and leak currents were subtracted either online using the P/4 method (F²⁹⁰W) or using an off-line subtraction (F²⁹⁰N and F²⁹⁰A). Gating current traces at the repolarizing pulses of the activation protocol are shown in an expanded time scale for the mutants F²⁹⁰N and F²⁹⁰A (insets).